scholarly journals THE RELATIONSHIP BETWEEN GROWTH AND MUTATION IN PSEUDOMONAS FLUORESCENS

1949 ◽  
Vol 58 (2) ◽  
pp. 171-180 ◽  
Author(s):  
Ellis Englesberg ◽  
R. Y. Stanier
Keyword(s):  
Pseudomonas Fluorescens ◽  
The Relationship

scholarly journals Features of the initial stages of the relationship between barley, phytopathogenic fungus Fusarium culmorum and rhizobacteria Pseudomonas fluorescens 2137

2020 ◽  
Author(s):  
A. I. Shaposhnikov ◽  
N. A. Vishnevskaya ◽  
V. Yu. Shakhnazarova ◽  
D. S. Syrova ◽  
E. V. Borodina ◽  
...  
Keyword(s):  
Pseudomonas Fluorescens ◽  
Root Exudates ◽  
Plant Defence ◽  
Fusarium Culmorum ◽  
Phytopathogenic Fungus ◽  
The Relationship

It was shown that enhanced colonization of barley's roots by Fusarium culmorum in the presence of Pseudomonas fluorescens 2137 may be due to the composition of root exudates. Strain 2137 can enhance expression of plant defence gene PAL.

scholarly journals Comparison of Three Methods for Monitoring Populations of Different Genotypes of 2,4-Diacetylphloroglucinol-Producing Pseudomonas fluorescens in the Rhizosphere

2002 ◽  
Vol 92 (2) ◽  
pp. 129-137 ◽  
Author(s):  
Blanca B. Landa ◽  
Henricus A. E. de Werd ◽  
Brian B. McSpadden Gardener ◽  
David M. Weller
Keyword(s):  
Pseudomonas Fluorescens ◽  
Limit Of Detection ◽  
Root Weight ◽  
Population Densities ◽  
Colony Hybridization ◽  
Specific Pcr ◽  
Hybridization Procedure ◽  
Polymerase Chain ◽  
Endpoint Assay ◽  
The Relationship

Pseudomonas fluorescens strains producing the antibiotic 2,4-diacetylphloroglucinol (DAPG) have biocontrol activity against a broad spectrum of root and seedling diseases. In this study, we determined the effect of genotype on the ability to isolate and quantify introduced 2,4-DAPG producers from the rhizosphere of wheat using three different methods: traditional dilution plating on selective media, colony hybridization followed by polymerase chain reaction (PCR), and phlD-specific PCR-based dilution endpoint assay. Regression analysis of the population densities of 10 2,4-DAPG-producing P. fluorescens, representing five genotypes, determined by the three different methods demonstrated that the relationship was linear (P < 0.001) and the techniques were very similar (i.e., slopes equal to 1.0). The phlD-specific PCR-based assay had a slightly lower limit of detection than the other two methods (log 3.3 versus log 4.0 CFU/g of fresh root weight). With the colony hybridization procedure, we observed that the phlD probe, derived from strain P. fluorescens Q8r1-96, hybridized more strongly to colonies of BOX-PCR genotypes D (strains W2-6, L5.1-96, Q8r1-96, and Q8r2-96) and K (strain F113) compared with strains of genotypes A (Pf-5 and CHA0), B (Q2-87), and L (1M1-96 and W4-4). Colony hybridization alone overestimated the actual densities of some strains, thus requiring an additional PCR step to obtain accurate estimates. In contrast, population densities estimated for three of the bacterial treatments (strains CHA0, W2-6, and Q8r2-96) with the PCR-based assay were significantly (P < 0.041) smaller by 7.6 to 9.2% and 6.4 to 9.4% than population densities detected by the dilution plating and colony hybridization techniques, respectively. In this paper, we discuss the relative advantages of the different methods for detecting 2,4-DAPG producers.

Effect of Pseudomonas fluorescens on Beef Discoloration and Oxymyoglobin Oxidation In Vitro†

1998 ◽  
Vol 61 (10) ◽  
pp. 1341-1346 ◽  
Author(s):  
WENDY K. M. CHAN ◽  
SEON-TEA JOO ◽  
CAMERON FAUSTMAN ◽  
QUN SUN ◽  
ROBERT VIETH
Keyword(s):  
Oxygen Consumption ◽  
Pseudomonas Fluorescens ◽  
In Vitro Study ◽  
Water Control ◽  
Peptone Water ◽  
Longissimus Lumborum ◽  
Reaction Vessels ◽  
The Relationship ◽  
Partial Oxygen

The relationship between bacterial growth and oxymyoglobin oxidation in vitro and in meat was studied. In the in vitro study, oxymyoglobin was combined with Pseudomonas fluorescens or sterile nutrient broth (control) in an airtight vessel. P. fluorescens samples showed greater metmyoglobin formation and oxygen consumption than controls. The P. fluorescens population in the reaction vessels was correlated with metmyoglobin formation (r = 0.85, P &lt; 0.05) and oxygen consumption (r = 0.91, P &lt; 0.05). When P. fluorescens and oxymyoglobin were combined in an airtight vessel, reducing the headspace from 13 ml and 9 ml to 3 ml resulted in greater metmyoglobin formation (P &lt; 0.05). In the meat study, beef cores prepared from longissimus lumborum were inoculated with P. fluorescens (107 CFU/cm2) or sterile peptone water (control), packaged under 1 % O2 (+99% N2), air, or 100% O2 and stored at 4°C. Inoculated beef cores showed higher bacterial loads and metmyoglobin formation than their respective Controls during 10 h storage in 1% O2, 3 days in air, and 7 days in 100% O2 (P &lt; 0.05). This finding indicated that P. fluorescens could accelerate beef discoloration. Overall, studies demonstrated that oxygen consumption concomitant with P. fluorescens growth decreased partial oxygen pressure, which accelerated oxymyoglobin oxidation.

Interstellar gas in the central region of the Galaxy

1967 ◽  
Vol 31 ◽  
pp. 239-251 ◽  
Author(s):  
F. J. Kerr
Keyword(s):  
Central Region ◽  
Galactic Plane ◽  
Neutral Hydrogen ◽  
Continuum Emission ◽  
Galactic Centre ◽  
Interstellar Gas ◽  
Hydrogen Recombination ◽  
The Galaxy ◽  
Centre Region ◽  
The Relationship

A review is given of information on the galactic-centre region obtained from recent observations of the 21-cm line from neutral hydrogen, the 18-cm group of OH lines, a hydrogen recombination line at 6 cm wavelength, and the continuum emission from ionized hydrogen.Both inward and outward motions are important in this region, in addition to rotation. Several types of observation indicate the presence of material in features inclined to the galactic plane. The relationship between the H and OH concentrations is not yet clear, but a rough picture of the central region can be proposed.

The relationship of the scleractinian corals to the rugose corals

Paleobiology ◽  
1980 ◽  
Vol 6 (02) ◽  
pp. 146-160 ◽  
Author(s):  
William A. Oliver
Keyword(s):  
Critical Points ◽  
Scleractinian Corals ◽  
Convincing Evidence ◽  
Early Triassic ◽  
Rugose Corals ◽  
History Of ◽  
The Subject ◽  
Relationship Of ◽  
The Relationship ◽  
Biologic Factors

The Mesozoic-Cenozoic coral Order Scleractinia has been suggested to have originated or evolved (1) by direct descent from the Paleozoic Order Rugosa or (2) by the development of a skeleton in members of one of the anemone groups that probably have existed throughout Phanerozoic time. In spite of much work on the subject, advocates of the direct descent hypothesis have failed to find convincing evidence of this relationship. Critical points are:(1) Rugosan septal insertion is serial; Scleractinian insertion is cyclic; no intermediate stages have been demonstrated. Apparent intermediates are Scleractinia having bilateral cyclic insertion or teratological Rugosa.(2) There is convincing evidence that the skeletons of many Rugosa were calcitic and none are known to be or to have been aragonitic. In contrast, the skeletons of all living Scleractinia are aragonitic and there is evidence that fossil Scleractinia were aragonitic also. The mineralogic difference is almost certainly due to intrinsic biologic factors.(3) No early Triassic corals of either group are known. This fact is not compelling (by itself) but is important in connection with points 1 and 2, because, given direct descent, both changes took place during this only stage in the history of the two groups in which there are no known corals.

Choosing a Markov blanket

2020 ◽  
Vol 43 ◽  
Author(s):  
Thomas Parr
Keyword(s):  
Markov Blanket ◽  
Target Article ◽  
The Relationship

Abstract This commentary focuses upon the relationship between two themes in the target article: the ways in which a Markov blanket may be defined and the role of precision and salience in mediating the interactions between what is internal and external to a system. These each rest upon the different perspectives we might take while “choosing” a Markov blanket.

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